Please, forgive the pun. However, geology can be an exciting topic to teach. Last week I visited a third grade classroom at
Kimberly Elementary School in Atlanta, Georgia. I was asked by the teacher to facilitate a lesson on rocks. Of course, I wanted to do something that would get the students engaged and excited, challenge them to think critically, and provide them with an opportunity to learn a bit about rocks. After scratching my head for a couple of days, I struck up a conversation with another fantastic science educator, Dr. Olga Jarrett, about the task at hand. To my surprise, Olga had created an incredible set of learning centers on the subject of rocks! She called the lesson
Performing Rocks. At each of the learning centers, the students had the opportunity to explore a specific rock and learn about its very special properties. With Olga’s permission, I borrowed her wonderful creation and set off to Kimberly to share it with the students. I can’t begin to tell you how excited the students were about the lesson. They had been reading about rocks in class, so they knew quite a bit. However, the Performing Rocks gave them an chance to explore rocks in a manner that was much more hands-on and apply some of what they had learned!
I thought I might take second and share with you some of the performing rocks used in Olga’s learning centers. I’ve also included a couple of my own additions.
Ulexite: Ulexite is a desert mineral that combines calcium, sodium, water molecules, and boron in a complicated arrangement. This rock is also known as “TV rock.” Ulexite consists of thin crystals that act like optical fibers, so if you lay it on a page of text, the printing appears projected on the upper surface (like a TV).
Biotite (Black Mica): Biotite is an iron-rich version of muscovite. It is named in honor of Jean Baptiste Biot, a French physicist who first described the optical effects in the mica minerals. When placed between two polarizing filters, biotite creates beautiful patterns of color.
Graphite: Graphite is pure carbon in a crystal form much like that of mica - sheets of strongly linked atoms, with very weak bonds between the sheets. This structure allows graphite to rub off on paper very easily. You can actually write with naturally occurring graphite. That’s why we use graphite in our pencils!
Calcite (also known as Iceland Spar): Calcite is calcium carbonate (CaCO3). Iceland spar is named after classic occurrences in Iceland, where fine calcite specimens can be found as big as your head. If you place Calcite on a sheet of text, the letters behind the calcite are offset and doubled.
Chalk: Chalk is a soft, white, porous form of limestone composed of the mineral calcite. Blackboard chalk, is currently made from the mineral gypsum (calcium sulfate) rather than calcium carbonate. However, you can draw with naturally occurring chalk.
Pumice: Pumice is basically solidified lava froth. Pumice looks solid, but it’s full of pores and spaces and weighs very little. In fact, some pumice will float in water.
Geode: Geodes are essentially rock cavities with internal crystal formations. The exterior of the most common geodes is generally limestone or a related rock, while the interior contains quartz crystals. If you shake a geode, you may hear the quartz crystals rattling around on the inside.
Halite: Halite is natural salt, sodium chloride (NaCl). Salt crystals look like tiny cubes under a microscope. Did you know that some rocks are edible?
Oil Shale: Oil shale is a general term applied to a group of rocks rich enough in organic material (called kerogen) to yield petroleum. If you scratch the surface of oil shale with your fingernail, you can smell oil. Imagine that…a scratch and sniff rock!
Talc: Talc is the softest mineral. Your fingernail will easily scratch it. Talc has a greasy feel and a translucent, soapy look. Baby powder or talcum powder can be created by rubbing two pieces of talc together.
For most teachers, finding rock samples for their classrooms proves to be difficult. Here are some suggestions for building your collection.
Start at Home: Some of the most interesting rocks can be found in your own backyard. Recently, I visited a school that had pieces of brown mica on playground. Building a rock collection with local rocks and minerals makes geology relevant to your students. It is also the cheapest way to begin your collection.
Rock Shows: No…I am not talking about that kind of rock show. You won’t find drums and electric guitars here. You will find lots of interesting rocks, minerals, and fossils. Most cities have geological societies that sponsor annual or semi-annual shows. Many of these shows are intended to help teachers learn about rocks and build their classroom collections. Check the internet (e.g. check this site) for the rock shows in your community.
Rock Swaps: Some teachers have discovered that there are other teachers around the country that are willing to swap rock samples through the mail. Some of these teachers have started their own swapping communities. Others have joined communities that are already up and running (I found this one while searching the net). Either way, trading rocks is a great way to build your collection.
